1) Combine the poaching liquid ingredients in a sauce pan and simmer uncovered for 20 minutes.

2) Place the salmon fillets in a single layer, in a wide saute pan. Pour over enough of the poaching liquid to cover by 1/2 inch.

3) Bring to a gentle simmer and poach 15 minutes until the fish is cooked through. Make sure that the liquid never boils. It should remain at 180 degrees.

4) Transfer the fish to a wide platter, spoon a little of the poaching liquid over the fish. Place a slice of carrot and a few pieces of onion on each fillet and cool to room temperature. Cover and refrigerate until chilled. The fish can be poached up to 2 days before serving.

5) Make the sauce: combine crème fraiche, mustard and chopped dill in a small bowl. Season to taste with horseradish. Serve the fish with crème fraiche.